java - JPA not persisting entity -

I am trying to save database changes made in a different unit. The objective of the unit is given by the argument (designated as data):

  generate private bullion (common game data data) {Boolean results = true; EntityManager em = HibernateUtil.currentEntityManager (); Try {em.getTransaction (). Start (); Em.merge (data); Em.flush (); ... some changes in the data object ... em.persist (data); Em.flush (); Committed to em.getTransaction (). } Hold (ex before) {... return false; } Back true; }   
 As I've read that I am using a different unit, I must first merge. But after work is done successfully, I do not see any change in the database. Where's the mistake?   
 
 
 As you do not save a new unit (by your comment), you do  No need to continue to call () . Apart from this I did not see any reason to make 'some changes' after calling  merge () , so I called  merge ()  after those changes. > Therefore, try the following:  
  em.getTransaction (). Start (); ... some changes in the data object ... em.merge (data); Em.flush (); Committed to em.getTransaction ().   
 Also very important: if you re-use a  ThreadLocal  variable with  EntityManager , then you have the last transaction Kind things should be taken care of (at least clear it + maybe close it) If the bug still persists, try to recreate one unit manager.